Seychelles' 115 islands fall under two distinct groups. The tall granite, Inner Islands cluster mainly within the relatively shallow Seychelles' plateau, 4° south of the equator and roughly 1800 km. distant from the east coast of Africa while the low-lying coralline cays, atolls and reef islands of the Outer Islands lie mainly beyond the plateau up to 10° south of the equator.

These Outer Islands are divided into five groups: the Amirantes group lying 230km distant from Mahé, the Southern Coral Group, Alphonse Group, Farquhar Group and finally the Aldabra Group, some 1150km from Mahé.

There are 43 Inner Islands in all -- 41 granitic and 2 coralline and a total of 72 coralline Outer Islands.